Conventional Y-branch type planar lightwave circuit (PLC) splitters often require quartz wafer substrates to minimize polarization dependent loss (PDL). However, these types of splitters may exhibit higher insertion losses. Y-branch type splitters require longer waveguide sizes as the number of splits increases, resulting in greater insertion losses. Moreover, quartz wafer substrates can be more expensive compared to Si substrates. Quartz substrates can also be brittle.
The present invention addresses these problems, by providing a funnel-type PLC optical splitter with lower PDL, lower insertion loss, and which can advantageously be formed on a silicon substrate.